Protein and amino acid metabolismDietary protein, endurance exercise, and human skeletal-muscle protein turnoverRodriguez, Nancy R; Vislocky, Lisa M; Gaine, P CourtneyAuthor Information Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut, USA Correspondence to Nancy R. Rodriguez, PhD, Associate Professor, Nutritional Sciences, Unit 4017, University of Connecticut, Storrs, CT 0626-4017, USA Tel: +1 860 486 0120; fax: +1 860 486 3674; e-mail: [email protected] Current Opinion in Clinical Nutrition and Metabolic Care: January 2007 - Volume 10 - Issue 1 - p 40-45 doi: 10.1097/MCO.0b013e3280115e3b Buy Metrics Abstract Purpose of review Whereas diet and exercise have been shown to influence whole-body protein utilization, little is known about the impact of these factors on skeletal-muscle protein turnover. We highlight the role of dietary protein in modulating skeletal-muscle protein turnover in response to endurance exercise. Effects of endurance exercise on skeletal-muscle protein metabolism are presented and the influence of habitual protein intake on exercise-related protein responses is discussed. Recent findings Skeletal-muscle protein turnover increases in response to endurance exercise training and following a single endurance exercise bout. Nutritional supplementation postexercise favorably affects skeletal-muscle protein synthesis and demonstrates amino acid availability as pivotal to the skeletal-muscle synthetic response following exercise. The level of habitual protein intake influences postexercise skeletal-muscle protein turnover. Summary Dietary protein and exercise are powerful stimuli affecting protein turnover. Since variation in habitual protein intake influences skeletal-muscle protein turnover postexercise, investigations are needed to determine what role protein intake has in regulating skeletal-muscle protein metabolism. Long-term, well controlled diet and exercise intervention studies are essential for clarification of the relation between protein intake, endurance exercise, and skeletal-muscle protein turnover. Studies designed to characterize this relationship should be attentive to habitual macronutrient and energy intakes. © 2007 Lippincott Williams & Wilkins, Inc.